[services] Rust Integration - Backup - c++ - Use uuid instead of current timestamp when generating log id

Summary:
Depends on D5072

I used to have duplicated log ids which lead to errors. This was because they could be sent in such a small interval that they'd have the same timestamp in their IDs. Using UUID solved this problem.

Test Plan: services build

Reviewers: jon, tomek, max, varun

Reviewed By: tomek

Subscribers: ashoat, tomek, atul, abosh

Differential Revision: https://phab.comm.dev/D5073